Method of hydrogenating pinene resin



Patented Mar. 4, 1947 METHOD OF HYDROGENATING PINENE RESIN William H.Carmody, deceased, late of Springfield.

Ohio, by Marie 0. Carmody, admlnis tratrix,

Springfield, Ohio, asslgnor to Carmody Research Laboratories, Inc.,Springfield, Ohio, a

corporation oi Ohio No Drawing. Application December 3, 1943,

Serial No. 512,784

3 Claims. 1

This invention relates to the hydrogenation of pinene resin. Theapplication herein is a continuation-in-part oi the application ofWilliam H. Carmody, Serial No. 280,128, filed June 20, 1939.

Pinene resins, by which is meant those terpene I resins of varyingmelting point which are composed oi terpene polymers having the formula(CloHi6)a and respond to the pinene structure, and which are representedchiefly by resins composed preponderantly of polymers of betapinene,alpha-pinene, and mixtures of them, previously have been hydrogenatedunder the catalytic effect 01' Raney nickel catalyst and similar metalcatalysts, as is patent of Marie 0. Carmody, No. 2,249,112, dated July15, 1941.

Pinene resins are of good light color and do not tend to yellowing in anorder which detracts substantially from their utility. They also havegood solubility in aliphatic hydrocarbon solvents. such as petroleumbenzine and the like. One deteriorating efiect to which pinene resinsare subject on aging is oxidation, which leads to the development ofembrittlement or incompatibiiity in compositions in which the pineneresin is included. The most active metal hydrogenation catalyst forresins. which is Raney nickel, is relatively expensive to use because ofits initial high cost, its susceptibility to catalyst polsons, and thedlfllculties attendant upon its storage.

The object of this invention is to provide a method of hydrogenatingpinene resin in a manner eilectively to inhibit oxidation in the resinon aging under the hydrogenation-inducing eil'ect of a catalyst practicewith which is less expensive than with Raney nickel, and hydrogenationwith which is adequately effective in preparing pinene resin for certainassociations and uses.

In accordance with this invention, hydrogenatlon of pinene resin isconducted in the presence of and under the catalytic effect of blackcopper oxide. It was not to be anticipated that this catalyst wouldexercise a hydrogenation-inducing enect under the moderate temperatureconditions requisite for the hydrogenation of pinene resin. The generalpractice in the use of the metal oxide catalysts. such for example asthe metal chromite catalysts and copper oxides. is to hydrogenate atrelatively high temperature, and the pinene polymers show a. markedtendency to decompose at temperatures above 250 C. and below those atwhich hydrogenation under the influence of metal oxide catalystspreviously has been conducted, as in the synthesis of methanol and likeprocesses involving a hydrogenation step. It is, however, the discoveryherein disclosed that the hydrogenation of pinene resin may be conductedunder moderate conditions in the presence of black copper oxide catalystwith the result of moderately hydrogenating the resin to an extentsatisfactory in p ecluding subsequent oxidation in the resin.

It is noteworthy that no special care of the catalyst is required; thatis, it does not have to be preserved under special conditions as is thecase with Raney nickel catalyst. Black copper oxide is not as energeticin its catalytic eflect as metallic nickel. and in the hydrogenation ofpinene resins tends to cause the introduction of hydrogen only intothose points in the resin molecule which are most easily attacked.Experiment has shown that with all the catalysts of this group thequantity of catalyst used should be approximately 5% to 30% the weightor the resin subjected to hydrogenation, 5% of the catalyst beingsubstantially the minimum with which the desired result will be secured.Although a percentage of the catalyst greater than 30% may be used. suchgreater percentage is under most circumstances unnecessary and performsno commensurately improved function in the hydrogenation reaction.

On the basis of a pinene resin having a melting point of about 95 C. to125 C. (ball and auaaoa ring) and considering specifically a pineneresin having an average molecular weight of about 800, 1.5 mole. ofhydrogen can be introduced without dimculty by means of black copperoxide into each molecular equivalent oi the pinene resin. With moredifilculty, as much as 3 mols. or more oi hydrogen can be introduced(other conditions being appropriate) by raising the temperature as highas is possible without decomposition of the resin and exercising carethat the temperature does not exceed the permissible maximum whileconductins the operation under relatively high pressure. With thelower-melting pinene resins, the molecular proportion of hydrogenintroduced tends to be lower under the same hydrogenating conditions,but 11- my case,

it is practical to introduce about .5 mols. 01' hydrogen into pineneresins of all molecular weights. Also, it has been found that blackcopper oxide may be used with anyone or more of the catalysts comprisedin the group of copper chromite, iron chromite, and nickel chromite.

In exemplifying the invention by means of the several specific exampleshereinafter set forth, a uniform procedure was followed in order thatthe results might be comparative in their illustration. In the procedureoi all the iollowing examples, save those in which some step wasunnecessary, a standard hydrogenation bomb was used; the resin wasground: and the ground resin, together with solvent and catalyst, wasplaced in the bomb and the bomb then closed. Hydrogen gas was admittedto the bomb from a suitable supply, as irom cylinders of compressedhydrogen, at the pressure desired for each particular experiment. Thewhole assembly was then placed in rotating mechanism of suitablewellknown kind and was warmed by gas burners. The bomb was fitted with athermometer well carrying a thermometer in the usual manner.

During the progress of the hydrogenation, the rotating mechanism wasstopped at intervals to observe data as to time, pressure, andtemperature. When the reaction was completed, as indicated by cessationoi pressure drop within the bomb, the temperature was restored to itsinitial value and the pressure was again observed. The catalyst wasremoved from the reaction solution by filtration and the solvent wasremoved by steam distillation. These procedures yielded a moltenresidual resin which was poured into a pan to harden. In operating toobtain recordable data, the usual precautions were taken to insure thatthe experiments were as quantitative as possible, and the bomb,therefore, was careiully calibrated to volume, and the volume of thereaction mixture deducted from it. The figure so secured represented thehydrogen gas volume in the bomb, which calculations gave the number ofcubic centimeters of hydrogen gas employed.

To illustrate the invention, a, hydrogenation treatment was conducted ona monomeric pinene fraction boiling from about 160 C. to 168 C.

Example 1 101.7 grams of the above noted pinene fraction was placed inthe bomb without diluent and with grams of black copper oxid catalyst.The maximum temperature of the reaction was 101' C. The initial pressurewas 1015 lbs. per square inch, and the final pressure was 720 lbs. persquare inch. 18,260 cc. of hydrogen was absorbed.

In figuring the above absorption of hydrogen, the charge composed oi thepinene and the black copper oxide was placed in a bomb having a volum:01' 920 cc. The volume of charge was cc.. thus leaving a space having avolume of 820 cc. for the hydrogen gas. The run showed a pressure dropof 315 lbs. per square inch over the course of the reaction. 315 lbs.divided by 14.7 (1 atmosphere of pressure) equals 21.43. This multipliedby 820 with appropriate correction equals 18,260 cc. of hydrogen.Theoretically 109% hydrogenation at the double bond 01 the pinenemolecules is thus shown.

Apparently there is an alkene double bond in the monomeric units 01'both alpha-pinene and beta-pinene which remains alter polymerization inthe terminal unit of each oi the pinene polymers. Considering as appearsto be a fact that this allrene double bond represents the point at whichoxidation and other reactions proceed most readily, substantialadvantage is obtained by hydrogenating in an order which substantiallysaturates that most susceptible point of attack. In hydrogenating pineneresin, however, it is a matter of general desirability to introduce asmuch hydrogen as may be done in the presence of the catalyst specifiedwithout utilizing conditions so drastic that they tend towarddepolymerlzation or disintegration of the pinene polymers. Inbydrogenating the pinene polymers, it has been iound'that the quantityor black copper oxide catalyst used, the pressure employed, and themaximum temperature at which hydrogenation is conducted, as well as thetime of treatment, are important factors.

In conducting a series of experiments as illustrated in the followingexamples, it has been found that about 90 C. is the temperature at whichhydrogen absorption begins to be substantial without using anunreasonably great quantity of catalysts, or unreasonably extending thetime of treatment, or unreasonably increasing the pressure under whichthe hydrogenation is conducted. About 225 C. is the maximum temperaturewhich may be used while insuring against de-polymerization o! the resin.The desirable temperature range for the hydrogenation reaction maytherefore be given as from about 90 C. to 225" C., and advantage isobtained by conducting the hydrogenation treatment stepwise,hydrogenating first at a temperature up to about C, to 200 C., and thenincreasing the temperature when hydrogen absorption lags up to about 225C. as a maximum. In conducting the hydrogenation, black copper oxidedesirably is used in quantities of from 5% the weight of the resin to30% the weight of the resin. It the quantity of catalyst used is as lowas about 5% the weight oi the resin, compensatory high pressure and hightemperature should be employed in the hydrogenation treatment. In noinstance is it desirable to employ a pressure substantially exceeding2100 lbs. per square inch.

In the following composite example, the pinene resin used was a pineneresin polymerized from a cut oi gum spirits of turpentine boiling withinthe approximate range of C. to 168 C., which pinene resin had a meltingpoint of 125 C., and a molecular weight of 800. That resin was dissolvedin petroleum benzine ior hydrogenation, and black copper oxide was usedas the catalyst. The bomb used had a capacity of 920 cc., and the volumeof each charge was close to 200 cc., leaving an approximate volume oi720 cc. available for hydrogen gas within the bomb. The exampleillustrates the control oi hydrogen- 5 ation with black copper oxidecatalyst by varying the quantity of catalyst used, the pressure underwhich the hydrogenation is conducted, the temperature of thehydrogenation, and the time of such as a pinene resin melting from about90 0.

(ball and ring) to 125 C. (ball and ring), the tendency toward oxidationis not great, and hydrbsenation in an order as above eflected re- Theforegoing example illustrates that as the factors of temperature andpressure are increased, that is, as they become moredrastic, the greaterwill the amount of hydrogen be which is absorbed by the resin. This,also, is true in measure as to the quantity oi' catalyst used and thetime of treatment. At the higher temperatures and pressures and withlarger amounts of catalyst, correspondingly increased amounts ofhydrogen can be caused to combine with the pinene polymers of the resin.

It will be noted that in run of Example 2 the hydrogen absorption is9,700 cc. of hydrogen. That figure indicates an absorption of about 2.5mole. of hydrogen. In run (e) about 1 moi. of hydrogen is introduced,and in run (I) about 1.25 of hydrogen is introduced. In all exampleshydrogenation introduction is at least equal to about .5 mo].

It has been above noted that pinene resin unaltered by treatment doesnot become excesslvely discolored on using, and that the pinene resinunaltered by treatment has good solubility in the low-priced petroleumsolvents, such as petroleum benzine. An unaltered pinene resin does,however, exhibit some tendency toward oxidation treatment, thecombination of these factors being duces the tendency toward oxidationsufllcientiy varied in the several runs. 1 to improve the resinhydrogenated in the several Example 2 Initial Final Time 111 Max. Cc. fHRun No. Hydrngenator charge In. "em mum tam e as? (a) 1.020 m m 3,12099.5

(t)---- --i. 100cc PE 025 m as m 3,060 76.6 (c) 010 m 100 m 1, 120 4a. a

a 100 cc. PB 1, 000 96s s 10s 2, ass as, 0

10 g. CuO 100 g. plnene msiiL. L n 100 cc. PB 1.065 085 215 m a 950 as.0

I5 g. CuO I!!! g. pinene resin n 100 cc. PB 1.000 895 420 214 5,025 mo3. CuO g. pinone resin {100012. PB 990 805 no use 0,700 231.5

30 g. CuO

diii'erent exemplincations for dlii'erent uses and conditions of useanticipated for the resin. The higher-melting pinene resins, such forexample as those melting about 185 C. (ball and ring) and higher, areless susceptible to oxidation than the lower-melting pinene resins.Low-melting pinene resins, such as the oily resin composed chiefly ofpinene dimers. with some inclusion of plnene trimers and other of thelower pinene polymers, are more susceptible to oxidation than are thehigher-melting exemplifications, and with them, hydrogenation is ofincreased importance in insuring that the progress of oxidation will notdestroy their efleotiveness as plasticizers in compositions in whichthey are included. It will be seen from Example 3, which follows, thatthe hydrogenation of pinene dimer oil, which is a pinene resin meltingbelow 0 0., follows the same principles as are involved in hydrogenatingthe highermelting pinene resins in the presence of copper chromite. Thisexample, like Example 2, is a composite example including several runsconducted under dlflerent conditions to illustrate the order ofhydrogenation effected by controlling the several factors of pressure,temperature, quantity oi catalyst, and time of treatment which andinsofar as such oxidation may become subhave been above discussed.

Example 3 Per cent of H;

Run No. Hydrogenatorchsrgs gag: sg 'igg' entered at the double bond in1,015 045 3:40 4.500 sec too 812 165 217 0.300 74.0

(c) 1.0110 805 15a 14, can 114.0

stantlal, it detracts from the aging properties of the resin and manycompositions in which it is included. In the higher-melting pineneresins.

It will be observed that in all the runs of Example 3, the introductionor hydrogen was in a molecular proportion 01 at least .5 mol. to eachresin molecule, at least two of the three factors 01' pressure,temperature, and quantity of catalyst being greater than is necessary inobtaining the same proportional saturation of double bonds in thehigh-melting resin 01 Example 2.

The above is further evidence of the fact that the general efl'ect ofincreased pressure, like that of increased temperature, is to induceincreased quantities of hydrogen to be absorbed by the resin, and thatother things being equal, this result is also roughly proportional tothe use oi increased quantifies of catalyst. Thus in run (c) of Example3 above, a very large quantity of catalyst is used, and this largeproportional amount of catalyst is accompanied by the condition of highpressure for the hydrogenation. In run (b), a large quantity of catalystis used, the pressure is relatively high, and the temperature approachesthe maximum permissible temperature for the hydrogenation.

The above consideration oi. the hydrogenation oi pinene resin in thepresence black copper oxide catalyst shows that there is close parallelbetween the hydrogenation of this resin and the hydrogenation ofcoumarone-indene resin as disclosed in companion application Serial No.512,787, filed Dec. 3, 1943. Whereas the existence of a terminal alkenedouble bond in the pinene polymer has been assumed, the presence or suchlone terminal double bond is not so thoroughly established as is thepresence of an analogous bond in the polymers of coumarone and indene.It is. however, a. fact that the two resins (the pinene resin and thecoumarone-indene resin) act so analogously under hydrogenation in thepresence of black copper oxide catalyst that the retention of suchalkene double bond, or analogous point oi attack, in the pinene polymersappears to be a reasonable and relatively safe assumption,

The above discussion and examples deal with and exemplify the use ofhydrogenation in the presence of black copper oxide as the sole catalystused, and demonstrate the satisfactory effect of hydrogenation in thepresence of that catalyst. It is to be understood, however, that thehydrogenation may be conducted in the simultaneous presence of blackcopper oxide and one of the chromite catalysts, the use of which isdisclosed and exemplified in companion application Serial No. 512,785,filed Dec. 3, 1943. That is, the black copper oxide may be used invaried proportions with one or more of copper chromite, iron chromite,and nickel chromite. When so used the diversity in the combined catalystappears to give a catalyst-promoting eiTect, so that a given quantity ofthe combined catalyst is somewhat more eil'ective than the same quantityof either catalyst alone. That is, the simultaneous use of black copperoxide and one or more catalysts from the group consisting oi copperchromite, iron chromite, and nickel chromite appears to indicate that inthe presence of the other both the black copper oxide and the chromitecatalyst are slightly more eflective than either when used by itself.Insofar as quantity of such mixture, either made in advance or in thebomb, is concerned, it is desirable to follow the catalyst proportionsgiven above for black copper oxide when used alone. That is, it isdesirable to use a. weight of combined catalyst equal to from 5% to 30%the weight 01' the pinene resin which is subjected to treatment.

Without regard to the point of entry of th hydrogen into pinene resinmolecules, the property of pinene resin as to its resistance todiscoloration and solubility in aliphatic solvents renders anysubstantial hydrogen on or the resin useful. That is. any substantial bof the tendency toward oxidation, such as that resulting from theintroduction of about .5 mo]. 01' hydrogen into the resin molecule,substantially increases the value of the resin. The use 01' the blackcopper oxide catalyst which is of low cost, which presents no diflicultyin storage. and which functions under moderate conditions of temperatureand pressure, is. therefore, advantageous.

ltistobe'understoodthatintheiore oina' where melting point is givenwithout qualification,itistobetakenasdeterminedbytheball and ring methodoi melting point determination. It is explained that the term pinene"resin is to be taken as inclusive of resins composed of the polymers oieither alpha plnene, beta-pinene, or emixtureoithepolymersorthosesubstances, together with such incidental proportionsof other terpene components as are normally asso' ciated in manufactureoi the resin. Where pressure is given in pounds without explanation, itis to be taken as meaning pounds per square inch.

Where parts or proportions are given without express or impliedqualification as to comparison of volumes, it is to be taken that partsby weight is intended.

What is claimed is:

l. A method or hydrogenating polypinene resin which comprises the stepsof bringing and: resin into contact with hydrogen in the presence ofblack copper oxide under such temperature and pressure conditions aschemically to introduce about .5 mol. to 3 mols. of hydrogen permolecular equivalent of polypinene resin structure. the 5- drogenationbeing carried out at a temperature ranging from about C. to 225' C. andat an initial pressure not substantially exceeding 2100 pounds persquare inch.

2. A method of hydrogenating polypinene resin which comprises the stepsof bring ng Such resin into contact with hydrogen in the presence 01'black copper oxide under such temperature and pressure conditions aschemically to introduce about .5 mol. to 3 mols. or hydrogen permolecular equivalent oi polypinene resin structure, the hydrogenationcarried out at a temperature ranging from about 90 C. to 225 (2., beingeflected stepwise by controlling the temperature in such manner that itdoes not exceed the range 01' C. to 200 C. in the first stage thereof,with the balance of the hydrogenation being carried out at highertemperatures ranging up to about 225 C. and at an initial pressure notsubstantially exceeding 2100 pounds per square inch.

3. A method or hydrogenatlng polypinene resin which comprises the stepsof bringing such resin into contact with hydrogen in the presence 01'black copper oxide under such temperature and pressure conditions aschemically to introduce about .5 mol. to 3 mols. of hydrogen permolecular equivalent oi polypinene resin structure, the said polypineneresin being in dissolved form and the catalyst constituting at leastabout 5% to 30% by weight of the said resin, at a temperature of from 90C. to 225 C. and under a pressure not substantially exceeding 2100pounds per square inch.

MARIE 0. CARMODY, Administratria: of the Estate of William H.

Carmodp, Deceased.

REFERENCES CITED The following references are of record in the file ofthis patent:

Ellis, Hydrogenation of Organic Substances, UNITED STATES PATENTS 3rded., Van Nostrand 1930, page 158.

Number Name Date Durland et al.. J. Amer. Chem. Soc., vol 60, 2,152,533r o y W 28, 1939 pages 1501-5 (1938), as abstracted in Chem. Ab-2.249.112 dr. y 1941 5 stracts,vol.32, 1938, page 5824.

TH REFERENCES Tuda. et a1., Berichte 72 B, pages 716-23 (1938),

r as abstracted in Chem. Abstracts, vol. 33, page Waterman et aL, Rec.Trav. China, v01. 55, 4979 (193! pages 7 to 12 (1936).

Adkins et al., J. Ameri. Chem. Soc., vol. 53, 10 pages 1091 to 1095(1931).

Certificate of Correction Patent No. 2,416,902. lVIarch 4, 1947.

WILLIAM H. CARMODY, BY MARIE O. CARMODY, ADMIN ISTRATRIX It is herebycertified that error appears in the printed specification of the abovenumbered patent requiring correction as follows: Column 6, Example 3,second column thereof, the indistinct portion under the headingHydrogenator charge should appear as shown below- {100 g. dimer 10 g.CuO No solvent 100 g. dimer {20 g. C110 No solvent 100 g. dimer 30 g.CuO No solvent and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 8th day of July, A. D. 1947.

LESLIE FRAZER,

First Assistant Commissioner of Patents.

Ellis, Hydrogenation of Organic Substances, UNITED STATES PATENTS 3rded., Van Nostrand 1930, page 158.

Number Name Date Durland et al.. J. Amer. Chem. Soc., vol 60, 2,152,533r o y W 28, 1939 pages 1501-5 (1938), as abstracted in Chem. Ab-2.249.112 dr. y 1941 5 stracts,vol.32, 1938, page 5824.

TH REFERENCES Tuda. et a1., Berichte 72 B, pages 716-23 (1938),

r as abstracted in Chem. Abstracts, vol. 33, page Waterman et aL, Rec.Trav. China, v01. 55, 4979 (193! pages 7 to 12 (1936).

Adkins et al., J. Ameri. Chem. Soc., vol. 53, 10 pages 1091 to 1095(1931).

Certificate of Correction Patent No. 2,416,902. lVIarch 4, 1947.

WILLIAM H. CARMODY, BY MARIE O. CARMODY, ADMIN ISTRATRIX It is herebycertified that error appears in the printed specification of the abovenumbered patent requiring correction as follows: Column 6, Example 3,second column thereof, the indistinct portion under the headingHydrogenator charge should appear as shown below- {100 g. dimer 10 g.CuO No solvent 100 g. dimer {20 g. C110 No solvent 100 g. dimer 30 g.CuO No solvent and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 8th day of July, A. D. 1947.

LESLIE FRAZER,

First Assistant Commissioner of Patents.

